Composition and crystallization patterns of calcareous corpuscles of cestodes grown in different classes of hosts.

The chemical composition and the crystallization patterns of the calcareous corpuscles of four and six species of cestodes, respectively, have been studied. Considerable variations were found in both areas. These seemed to be more related to the species of tapeworm than to the type of host in which the worms grew. Thus, very pronounced differences were found between the corpuscles of two larval worms (Taenia crassiceps and Mesocestoides corti), both of which developed in the peritoneal cavity of mice. On the contrary, the crystallization patterns of one fish tapeworm (larval Ligula intestinalis) corresponded upon heating to 600 or 900 C to what is found in such mammalian species as Taenia taeniaeformis, Bertiella studeri, and several others. The 300 C pattern of Ligula conformed to that found in another mammalian species, Mesocestoides corti, and a similar pattern has not yet been encountered in any other tapeworm, of mammalian or nonmammalian origin. The corpuscles of the chicken tapeworm Raillietina cesticillus, on the other hand, were characterized by the almost complete absence of magnesium and the fact that ethylenediamine-isolated corpuscles showed a definite calcite pattern before subsequent heating. In other species, corpuscles isolated by this method have been amorphous with only those of Cysticercus cellulosae showing traces of calcite. Our previous studies (von Brand et al., 1960, 1965a, b; Scott et al., 1962) on the chemical composition and crystallization of cestode calcareous corpuscles revealed quantitative and qualitative differences between the granules isolated from certain species. All tapeworms studied so far in these respects had been grown in mammals. Thus the question arose whether corpuscles from cestodes isolated from other groups of hosts would show more pronounced differences or other types of differences. The present communication is a first attempt to present material having a bearing on this ques-